3D Printing in construction: Prospects and Challenges

The construction industry generates approximately $10 trillion in annual revenue, accounting for roughly 6% of global GDP. Indeed, engineering and construction are essential chevaliers of world economy and growth. Hence construction firms are always looking for new techniques to increase the output while lowering costs.

3D printing is the new solution for these issues.

3D printing, often known as additive manufacturing (AM), is one of the newest types of construction technology that has been introduced to the industry. Today, construction is being pushed towards automation to reduce labour; minimize on-site construction time; increase production; improve architectural freedom and lower costs. Furthermore, 3D printing contributes to environmental sustainability.

3D printing (3DP) is a layered material joining method that uses 3D model data to create diverse structures and complicated geometric patterns without the use of tooling, dies, or fixtures. The American Society for Testing and Materials (ASTM) and the International Organization for Standardization (ISO) define AM as "the process of combining materials to construct objects from 3D model data, usually layer by layer." With its potential for automation, formwork elimination, construction waste reduction, and geometrical precision enhancement, 3DP has a lot of promise for construction applications.

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A brief history of 3D printing technology

The first commercial 3D printing machine was built in 1986 by Charles Hull, an American scientist recognized as the "Father of 3DP". The experimental application of 3DP in the building industry began in the late 1990s. Existing 3DP research focuses on advanced materials (e.g., cementitious materials, polymer materials, and metal materials, processes (e.g., contour crafting, D-shape, and concrete printing), and implementation methods (e.g., off-site/on-site fabrication, hybrid techniques, and multiple materials). Novel shapes, topology optimization, bespoke parts, and in-situ repair are some of the construction applications.

3D printing techniques

AM employs a variety of manufacturing techniques. Contour Crafting, D-shape, Concrete Printing, and Shotcrete 3D printing are the four major 3D printing processes among them. Contour Crafting (CC) technology is the most promising 3D printing technique utilized in the construction industry. Material is poured layer by layer in this technology, yet the entire process takes place on-site. This technology offers a huge chance for construction process automation by using a 3D printer that can print a whole house on-site.

Benefits of 3D printing

The major advantages of 3D printing are explained as follows:

1. Time savings: The time taken to finish the building can be drastically reduced.

2. Cost savings

3. 3D printing gives you more geometric freedom to create structures that would not be possible otherwise.

4. Sustainability: 3D Printing allows for the creation of environmentally friendly designs and structures.

5. 3D printing decreases waste generated during the manufacturing process.

6. It also decreases the need for formwork.

7. Enhanced safety in the building sites as the printers will be capable of performing the majority of the hazardous and dangerous work

8. Time-efficient: wet construction procedures are eliminated, resulting in fewer material wastes and less time spent constructing buildings

Challenges of 3D printing

Despite having numerous benefits, 3D printing also has some limitations and challenges. They are explained as follows:

1. Material: the main challenges are related to the 3D printing material. The material issues can be broken down into three categories: printability, buildability, and open time. The material must have the desired printability and buildability in order to be extruded from the nozzle and maintain its shape. Other major issues are printability and constructability. The material must swiftly support itself, and the layers must generate sufficient connections between them. The third challenge is open time. The printability and buildability must be constant within acceptable tolerances during the open time.

2. Printer: There is just a limited amount of time to print the materials. Any delays may cause the concrete to harden. As a result, unique material combinations are required, as well as sufficient printing time. Scalability, directional dependency, and cyber security are all issues with 3D printers. The scale of construction projects adds to the difficulty of 3D printing.

3. Cyber security: The construction process is automated and all information is stored in a 3D model. Hence cyber security and the danger of hacking are a concern.

4. Exclusion of building services, structural integrity, and construction site suitability are all design and construction problems. Building services, such as electrical and mechanical, are difficult to exclude.

5. Another major issue is structural integrity. Because the quality of the printed parts have been discovered to be fragile, printing load-bearing components have proved problematic.

6. Another difficulty is establishing a construction location. The open environment of a construction site may not be suited for 3D printers that require a more regulated setting. Furthermore, site circumstances may be variable, making the relocation and installation of the 3D printer difficult.

7. 3D printing construction faces additional problems due to a lack of codes and regulations. There are no restrictions limiting the use of 3D printing in construction projects because the technology is still new.

8. New technology: It's difficult to imagine 3D printing replacing traditional buildings in the next few years. It is more likely that both technologies will be present in the sector, with 3D printing developing alongside older processes and supporting them, particularly in the case of more complex building projects.

Some notable 3D printing applications in the building industry

Canal House in Amsterdam

In 2014 Dutch design business Dus Architects decided to build a house by printing its elements via a huge 3D printer. This was the first project that will be realized solely by 3D printing technology In Europe. This 3D Print Canal House project was built in Amsterdam. Architects from Dus Architects want to show that by printing house components directly on the site, they can entirely eliminate construction waste and reduce transportation expenses.

The printer's mobility is seen as its primary benefit because it can be relocated anywhere in the world, reducing the cost of material transportation and storage on construction sites. The project's duration was calculated to allow them to research printing processes and manufacture appropriate materials. Because the major goal of the operation is to identify and share possible uses of 3D printing in the building sector, the construction site is accessible to the public and will remain open long after the project is completed.

WinSun Company buildings

WinSun Decoration Design Engineering Co is a Chinese firm, working on materials that are comparable to concrete and suitable to use in 3D printing technology. They have been successfully building numerous houses using their 3D printing technology since 2014. The building components are printed as prefabricated elements and assembled on site. They use a 3D printer for printing components that are 6 meters high, 10 meters wide, and 40 meters long. Layer by layer, the printer extrudes the material (mortar) through a nozzle.

The walls are diagonally reinforced, with a hollow structure acting as an insulation layer. Components are printed in a facility and then brought to the construction site where they are put together to form the entire structure. Then the building walls were fitted with windows and doors. After the roof was erected, finishing works were done and structures were completed. The anticipated cost of each structure is $4,800.

REFERENCES

• Izabela Hager, Anna Golonka and Roman Putanowicz; 3D printing of buildings and building components as the future of sustainable construction; Proceedia Engineering 151 ( 2016 ) 292 – 299

• Wikipedia, available from: https://en.wikipedia.org/wiki/Chuck_Hull (2016)

• 3D print canal house, available from: http://3dprintcanalhouse.com/construction-technique, (2016).

• WINSUN, available from: www.yhbm.com, (2016).

• B. Khoshnevis, Automated construction by contour crafting – related robotics and information technologies, Automat. Constr. – Special Issue: The best of ISARC 2002, 13 (2004) 5–19.

• Xin Ning; 3D Printing in Construction: Current Status, Implementation Hindrances, and Development Agenda; Advances in Civil Engineering, 2021

• Lotfi Romdhane and Sameh M. El-Sayegh, 3D Printing in Construction: Benefits and Challenges, International Journal of Structural and Civil Engineering Research Vol. 9, No. 4, November 2020